From: Alan Chandler <alan@chandlerfamily.org.uk>
To: Jens Axboe <axboe@suse.de>
Subject: Re: ide-cd problem
Date: Sun, 21 Nov 2004 00:53:44 +0000
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On Saturday 20 November 2004 19:47, Jens Axboe wrote:
> On Sat, Nov 20 2004, Alan Chandler wrote:
...
> > Normally, because the requested data_len is not zero, the data is
> > sent.  In this case however, because the original request had nothing
> > to send, the while/if clauses to initiate a new transfer are skipped
> > and the routine ends up setting a new interrupt handler address and
> > returning to await an interrupt that will never come.
>
> The big question is - what does the original command look like? Just
> dumping rq->cmd[0] would be a big help, but really just put code in
> sg_io() in block/scsi_ioctl.c to dump the completed sg_io_hdr_t and send
> that.

I haven't dumped the whole request header, but the command (after it has been 
retrieved from the user) and the dxfer_length.  Is there anything else I 
should dump?

Here is the output leading up to the point where ide-cd hangs because the IO 
is just left pending

Nov 21 00:44:20 kanger kernel: sg_io command length 10
Nov 21 00:44:20 kanger kernel: sg_io command [0] = 0x3c
Nov 21 00:44:20 kanger kernel: sg_io command [1] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [2] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [3] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [4] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [5] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [6] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [7] = 0xfc
Nov 21 00:44:20 kanger kernel: sg_io command [8] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [9] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io dxfer_len = 64512
Nov 21 00:44:20 kanger kernel: sg_io command length 10
Nov 21 00:44:20 kanger kernel: sg_io command [0] = 0x3c
Nov 21 00:44:20 kanger kernel: sg_io command [1] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [2] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [3] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [4] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [5] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [6] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [7] = 0xfc
Nov 21 00:44:20 kanger kernel: sg_io command [8] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [9] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io dxfer_len = 64512
Nov 21 00:44:20 kanger kernel: sg_io command length 10
Nov 21 00:44:20 kanger kernel: sg_io command [0] = 0x3c
Nov 21 00:44:20 kanger kernel: sg_io command [1] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [2] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [3] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [4] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [5] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [6] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [7] = 0xfc
Nov 21 00:44:20 kanger kernel: sg_io command [8] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [9] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io dxfer_len = 64512
Nov 21 00:44:20 kanger kernel: sg_io command length 10
Nov 21 00:44:20 kanger kernel: sg_io command [0] = 0x3c
Nov 21 00:44:20 kanger kernel: sg_io command [1] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [2] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [3] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [4] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [5] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [6] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [7] = 0xfc
Nov 21 00:44:20 kanger kernel: sg_io command [8] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [9] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io dxfer_len = 64512
Nov 21 00:44:20 kanger kernel: sg_io command length 6
Nov 21 00:44:20 kanger kernel: sg_io command [0] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [1] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [2] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [3] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [4] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [5] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io dxfer_len = 0
Nov 21 00:44:20 kanger kernel: sg_io command length 6
Nov 21 00:44:20 kanger kernel: sg_io command [0] = 0x1b
Nov 21 00:44:20 kanger kernel: sg_io command [1] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [2] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [3] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io command [4] = 0x3
Nov 21 00:44:20 kanger kernel: sg_io command [5] = 0x0
Nov 21 00:44:20 kanger kernel: sg_io dxfer_len = 0
Nov 21 00:45:00 kanger kernel: hdc: lost interrupt
Nov 21 00:45:40 kanger kernel: hdc: lost interrupt
Nov 21 00:47:00 kanger last message repeated 2 times
Nov 21 00:47:40 kanger kernel: hdc: lost interrupt


-- 
Alan Chandler
alan@chandlerfamily.org.uk
First they ignore you, then they laugh at you,
 then they fight you, then you win. --Gandhi
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